This invention relates to cone crushers used for crushing rocks and, more specifically, feed distributors used in combination with rock crushers and other devices.
Generally, a belt conveyor or feeder delivers rocks and stones into a crusher. The rocks will ride up the conveyor, whose end is located above the input of the crusher. The rocks are dumped under the force of gravity into the crusher, which will then break the rocks into a predetermined size. Preferably, the uncrushed rocks will first pass through a feed distributor, which will assist in dispersing the uncrushed rocks into the crusher.
Since rocks fed into the crusher are not always of the same size and shape, they will not necessarily be crushed to a final uniform size. However, it is preferable to have the crushed rocks be within a relative range and size; otherwise the rocks and stones need to be recrushed. Furthermore, the final crushed rock product should preferably have a uniform gradation of rock sizes and shapes, rather than having a batch of stones that may contain very fine dust as a product and another batch that only contains larger rocks. Such segregation of the rocks is not advantageous as it can lead to a less saleable end product. In the event the rocks are too large for specifications, the rocks will be recycled back into the crusher to be crushed again.
To alleviate problems of nonuniformity, previous designs and inventions have focused on improving the crushers so that the resultant crushed rocks will be more uniform in size. However, it has been observed that one of the reasons for inconsistent crushed rock gradation is that the uncrushed rocks are not evenly distributed as they fall into the crusher and instead arrive in the crusher in a segregated fashion. Rocks will generally fall into the crusher under the force of gravity, which means small rocks will fall together and larger rocks will separately fall together. Consequently, the rocks will not be evenly distributed, which leads to potentially uneven crushing of the rocks. Rocks outside of a predetermined range will need to be recycled or re-crushed, which is not an efficient process.
Premature wear of the specific parts of prior feed distributors is also a problem. When rocks fall upon the feed distributor and the chute used in the distributor, the impact tends to wear and erode the feed distributor's components. The rock crushing environment creates excess and abrasive dust which can also lead to premature wear of certain machine elements, such as bearings. As a result feed distributor components need to be replaced, which leads to more downtime of the system and, consequently, reduces the efficiency of the overall system.
Previous inventions, such as Sawant et al., U.S. Pat. No. 7,040,562, owned by the same assignee as the present invention, disclose rotating feed distributors. However, depending upon the environment where it is operated, the device in Sawant may require frequent maintenance. This is not desirable as the entire rock crushing process must be halted while the rotating feed distributor is attended to.
Other previous inventions, such as Ryan et al., U.S. Pat. No. 6,227,472, discuss devices that will spin rocks into the sides of the crusher. However, the device in Ryan causes buildup within the device, and, since the device is located within the crusher, is not easily cleaned or serviced. Other devices, such as Kemnitz, U.S. Pat. No. 4,106,707, contemplate feed distributors, but do not allow for control and efficiency as is found in the present invention. Furthermore, prior art designs have been observed to comprise drive means that are susceptible to dust and dirt and may unduly slip when driving the feed distributor, such as Gasparac et al., U.S. Pat. No. 3,212,720. The present invention addresses this issue by introducing a system for evenly distributing feed rocks into a crusher.